Engine construction



C. F. KETTERING ENGINE CONSTRUCTION July 15 1924.

Filed June 21,, 1919 I5 Sheets-Sheet. F

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Patented July 15, 1924.

UNITED STATES PATENT orrica.

CHARLES F. KETTERING, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GENERAL MOTORS RESEARCH CORPOBA'I'ION, OF DAYTON, OHIO, A CORPORATION OF DELAW ARE.

ENGmE CON STBUCTION.

Application filed June 2 1, 1818.

T 0 all whom it may concern.

Be it known that I, CHARLES F. Kerrsnme, a citizen of the United States of America. residing at Dayton, county of Montgomery, State of Ohio, have invented certain new and useful Improvements in Engine Constructions, of which the following is a full, clear, and exact description.

This invention relates to engines, and more particularly to the cooling of engines especially of the socalled, air-cooled type.

One of the principal objects of this invention is to provide an engine construction adapted to the proper cooling of the engine, and especially of the engine cylinders.

Other objects and advantages will be apparent from the description set out below, when taken in connection with the drawings.

In the drawings:

Fig. 1 is a view, partly in section, of an engine embodying my improved construction. including what I term an equalizer. and adapted for up-draft cooling;

Fig. 1 is a fragmentary view of Fig. l showing the equalizer and an insulator;

Fig. 2 is a view, similar to Fig. 1, in

which the engine is adapted for down-draft icooling;

Fig. 3 is a fragmentary view of a cylinder having a modified form of such equalizer;

Fig. 4 is a detail view of the equalizer shown in Fig. 3.; 1

Fig. 5 is still another modified'form of cylinder construction; and

Fig. 6 is a fragmentary view showing a form of finning.

This invention, for purposes of easier de scription, will be described in connection with an air-cooled internal-combustion en gine. It must be borne in mind, however, that the invention is not limited to the specific type of engine disclosed.

In the cooling of the conventional air cooled internal-combustion engine one of the primary problems which must be solved is the removal of heat from the engine cylinders to secure satisfactory working conditions. The cylinders of an internal-combustion on ine consist broadly of a barrel portion an ahead portion. The cooling of the cylinder barrel may be a comparatively simple matter, but the cooling of the cylinder head is much more difiicult. The flow of cool incoming gases through the inlet port Serial 1%. 805,782.

and of very hot out-going gases through the exhaust port tends to cause irregular heat distribution through the cylinder head, with consequent distortion due to irregular expansion. Appreciating the importance of this situation, and in order to secure satisfactory operating conditions, I aim to control the temperature of the cylinder head so as to maintain a uniform heat distribution thereover and to keep the peak temperature below a definite maximum. The superstructureand by superstructure I mean the valve mechanism, the inlet and exhaust pipes, the spark plugs, etc.--renders proper temperature control of the cylinder head extremely difficult.

In Fig. 1 is illustrated a type of air-cooled engine in which the cylinder is so constructed as'to secure proper cooling of both the cylinder barrel and the cylinder head. Ihe engine shown in Fig. 1 comprises a crank case 10 and a flywheel 11. Mounted upon the crank case is a cylinder 20, which may be of steel, cast iron or other suitable material. As shown this cylinder comprises a barrel portion 21 and a head portion 22. Carried by exhaust conduits 23, 24, which are controlled by the valves 25 and 26. Also carried by the head portion are the rocker arms 27, adapted for actuating the valves. These elements constitute what I call, the superstructure." Attached to the cylinder barrel is a plurality of radiating elements or cooling fins 30. These fins should be of some material which is a good conductor of'heat, and I prefer ably use copper, which has given very satisfactory results. By usin a fin material whichis such a good con uctor of heat as copper the thickness of the fins may be meterially decreased, and a greater, number of.

fins thus secured, with a consequentincrease in radiating surface, without loss in the oonductive capacity of the fins or in the capacity of the air passages between the fins. The fins are preferably formed from a single sheet of metal corrugated, or plaited, as shown in Fig. 6.- The form of fin shown is, of course, merely one form that may be used and any other type adapted to give a corresponding radiating surface and conductivity might be used just as well. In attaching the fins to the cylinder barrel the aim should be to provide an efi'ective thermal contact. It

the head portion are the inlet and is not suflicient that the fins and the cylinder barrel be in ordinary metal-to-metal contact, but their relation should be such that there will be little resistance to the How of heat from the cylinder into the fins. This desired condition I have, for convenience, termed eilective thermal contact. One manner of securing this effective thermal contact of the two materials is to weld or solder the fins to the cylinder, using any su1table solder, such, for example, as conventional silver, or lead-tin, solder. Other methods of securing such thermal contact may be utilized and in copending applications are described further ways of uccomplishing this result.

Attached to the head portion of the cyl inder is what, for convenience, I have termed an equalizer 35. The equalizer shown in Fig. 1 and Fig. 1 consists of a cupshaped member adapted to contact with the cylinder head, and the upper end of the cylinder barrel. This equalizer is composed of a material which is a good conductor of heat, preferably copper, and the object thereof is to equalize the heat in the cylinder head so as to give a uniform distribution of heat therein. By usin an equalizer which is a. good conductor of eat, and extendin the equalizer outwardly be yond the cy inder'wall it is possible to secure both a uniform distribution of heat over the cylinder head and a cooling of that cylinder head to thus lower the maximum peak temperature attained thereby. As shown in Fig. 1 the equalizer does not extend straight out but its outer edge is brought down into contact with the upper end of the cylinder barrel, the fins 30, at their upper ends being attached to the downturned portions of the equalizer. By this construction the heat carried off from the cylinder head by the ualizer is transferred to the fins 30 whence it is taken up by the cooling air, and a very substantial cooling of the cylinder head, thus secured. In attaching the equalizer to the cylinder head and the upper part of the cylinder barrel, the same efl'ective thermal contact should preferably be secured as is above described as being secured between the fins and the cylinder barrel. here a cast iron cylinder is used a very satisfactory manner of attaching the equalizer to the cylinder head is to use silver solder. This method of attachment also applies in the case of asteel cylinder. Where asteel cylinder isused the equalizer may also be attached by casting the copper upon the cylinder. Other ways of attaching the equalizer to the head portion of the cylinder may be used, several such ways being disclosed in copendin'g applications. The upper ends of the fins 30 should be in thermal contact'with the copper equalizer.

just as satisfactorily. The function of this insulator is to prevent the back flow of heat from the superstructure to the equalizer and cylinder head. Generally it is not necessary t at the entire superstructure be insulated from the equalizer and cylinder head, though it is usually simpler in'actual practice to so arrange the insulating material. It is very important, however, that the exhaust conduit be insulated. To assist in dissipating the heat within the walls of the exhaust conduit the cooling elements or fins 41 are arranged thereon.

Surrounding the cylinder and the fins carried thereby is a draft tube 45, the lower end of which is seated upon, and opens into, the crank case. Upon the operation of the engine there is a flow of cooling air through the draft tube, bringin a large quantity of air into contact with t e cooling elementsof the cylinder. For causing the desired flow of cooling air through the draft tube and over the cooling elements of the cylinder I preferably make use of a positive, or pressure, blower 50, having a delivery pipe 51, opening into the draft tube below the lower ends of the fins. This blower may be any of the approved or well known types, and, as illustrated, it is driven directly from the crank shaft of the engine, as by means of gears. In Fig. 1, a gear 52 is shown, carried by the crank shaft, which meshes with another gear, not shown, mount ed upon the shaft 53 of the rotor element of the blower. By properly proportioning the gears the blower may be operated at the speed necessary for delivering the desired quantity of cooling air through the draft tube. If desired other means for driving the blower may be used, for example, it may be driven from the fly wheel by means of a belt.

A c linder of the type described is not limite in its applicability to an engine furnishing up-draft cooling air but it will also operate satisfactorily with a downdraft. In 2 is shown an engine embodying my improved cylinder construction in which the flow of cooling air is furnished by a suction fan 60 incorporated in the fly wheel.' The structure shown in Fig. 2 is identical with that shown in Fig. 1, with the exception of the mechanism for causing a flow of cooling air. With the exception of the cylinder structure the device shown llil in Fig. 2 is similar. tothe engine structure illustrated and described in co ending application No..58,207, filed Octo r 27, 1915.

F "3 and 4 show a modified form of cylinder construction in 'which the equalizer is in the form of an up-turned cup35. This cup is attached to the cylinder head 22, in the same manner as described in connection with the cup shown-in Fig. 1. In making up a cup such as shown in Figs. 3 and 4 a disc of copper of the desired diameter and thickness, the dimensionsof the disc being dependent upon the cylinder dimenslons, is slit along its outer edge, the depth of the slits being-such as to leave the central, or non-slit, part 66 of the disc ofsuhstantially the same diameter as the cylinder head, and alternate slit portions 67 are then up-turned, as clearly shown in Fig. 4. This provides an equalizer in which every other slit portion is up-turned to provide, roughly, a cup, the slit portions not up-turned Igpjecting outwardly beyond the cylinder.

ese slit portions when in this form provide a species of fins or radiatin elements by means of which the heat istributed through the equalizer is more eficctively transferred into the cooling air. The up turned slit portions are so positioned that a lace is rovided for the inlet conduit an the ex aust conduit. Interposed between the upper surface of the equalizer cup and the lower surface of the cylinder superstructure is a layer of insulating mate rial 40, which insulating material, as described in connection with Fi 1, may be of asbestos, mica, or other ana ogous mate rial. The valve mechanism, the fins, shown in this modified form of apparatus are substantially identical with the corresponding parts shown in Fig. 1.

In Fig. 5 is shown still another modified form of cylinder construction in which the equalizer 35" is in the form of a plate or dlsc, instead of a cup as shown in Figs. 1, 2, 3 and 4. This equalizer is also of copper, or some other material which is a good conductor of heat. In this modified form of cylinder the fins, at their upper ends, contact with the equalizer late. The draft tube 45 and ou er faces 0 the fins 30 however, are cut away a short distance below the equalizer to permit of the passage of coolin air. In this modification, as in those descri ed above, a heat insulating member 40 is inserted between the upper surface of the'equalizer' plate and the lower surface of the su erstructure.

In ig. 6 is shown a fragmentary sectional view through the cylinder shown in Fig. 1, alon the line fi6. As shown in th1s figure t e cooling fins, which are attached to the equalizer and to the cylinder, are made from a continuous strip of material which is bent upon. itself, somewhat in etc.,

the form of accordion plaiting, each fold constituting a fin of the desired dimensions. The same type of fin is used in the modifications shown in Figs. 2, 4 and 5. Obviously the fins need not, of necessity, be made of co per inasmuch as any other material of su ciently good conductivity might be substituted therefor. And they need not be made from a continuous strip, separately formed fins being very satisfactory. Also two sets of fins may be used on each cylinder, one set for the equalizer and another set for the cylinder barrel, the fins bein so attached that the air assa es between t em are not obstructed. he us, however, regardless of their form or the material constitutin them, should preferably be in substantial y true thermal contact with the cylindcr.

While I have illustrated cylinders having vertical, or longitudinal, fins my invention is not limited to that particular structure, as I may also use circumferential fins. In such case the e ualizer would be similar to that shown in ig. 5, and would also function as a fin. This type of construction is peculiarly adaptable to airplane engines in which large quantities of an move over the cylinders as a. result of the ropeller action and the movement of the airplane through the air.

All of the cylinders described are adapted to function in the same general manner. The equalizer, regardless of its form, is composed of a material which is a good conductor of heat and is adapted to maintain substantially uniform the heat distribution throughout the cylinder head. And the fins should be of a material having the same characteristic.- Also both the equalizer and fins preferably be in effective thermal contact with the cylinder head. The equalizer need not be of dili'erent material, or a separate member, from the cylinder head, as substantially the same result could be secured with an equalizer which is integral with, and of the same material as, the head. But it is extremely important that the cylinder head he so constructed as to secure a uniform heat distribution thereover, and to provide some means for radiating a part of this heat into the cooling air.

While the insulator between the cylinder head, or ualizer, and the superstructure is not an a solute necessity, under all normal conditions it tends to secure more satisfactory operation of the engine. By preventing the back flow of heat from the exhaust conduit to the cylinder head and equal-' izer it permits of more uniform heat distribution through the equalizer and head and of more ready cooling of the head.

' While the forms of mechanism herein shown and described constitute preferred forms of embodiments of the invention, it

is to be understood that other forms might be adopted, all coming within the scope of the clalms which follow.

What I claim is as follows:

1. In an engine; a cylinder comprising a barrel portion and a head portion; a superstructure carried by said head portion; and insulating material between the head portion and the superstructure.

2. In an engine; a cylinder comprising a barrel portion and a head portion; an equalizer attached to the head portion; a superstructure carried by said head portion; and means for insulating the head portion from the superstructure to obstruct the transfer of heat therebetween.

3. In an engine, a cylinder comprising a barrel portion and a head portion; an equalizer attached to the head and in effective thermal contact therewith; a superstructure carried by the head; and heat in-. sulating material between the equalizer and the superstructure.

4. An engine cylinder comprising a barrel portion and a head ortion; a copper equalizer attached to t e head portion; a superstructure carried by the head portion; and heat insulating means between the equalizer and the superstructure.

5. An engine cylinder comprising a barrel portion and a head portion; an equalizer attached to the head portion, said equalizer being composed of a material which is a. good conductor of heat, and extending outwardlybeyond the cylinder to permit of more ready cooling thereof; a superstructure carried by the head; and heat insulating means between the equalizer and superstructure.

6. An en 'ne cylinder comprising a barrel portion an a head portibn; an equalizer attached to the head portion, said equalizer bein composed of a material which is a goo conductor of heat; cooling elements associated with the e ualizer; a superstructure carried by the has portion; and means interposed between the superstructure and the i e ualizer. for preventing the ready transfer 0 heat therebetween.

' 7. An en ine cylinder comprising a barrel portion and a head portion; an equalizer attached to the head portion, said equalizer 8. An engine cy in ler comprising a head portion and a barrel ortion; a cup-shaped' equalizer attached to t e head portion; cooling elements associated with the equalizer; a superstructure carried by the head portion; and means for preventing the ready transfer of heat between the equalizer and super structure.

9. An engine cylinder comprising a barrel portion; a head portion an. exhaust conduit carried by the head portion; and heat in sulating means for preventin the ready transfer of heat between the sad portion and exhaust conduit.

10. An engine cylinder comprising, a barrel portion; a head portion; an exhaust conduit carried by the head portion; and an insulator of asbestos between the head portion and exhaust conduit to prevent the ready transfer of heat therebetween.

11. In an air cooled engine, a. cylinder comprising a barrel portion no head portion having an equalizer, composed of a material which is a good conductor of heat, attached thereto; a superstructure carried by the head portion; heat insulating means between the equalizer and the superstructure; and means for causing a flow of cooling air along the cylinder toward the head portion thereof.

12. In an air cooled engine, a cylinder comprising a barrel portion; a head portion having an equalizer, composed of a material which is a good conductor of heat, attached thereto; a superstructure carried by the head portion; heat insulating means interposed between the equalizer and superstructure; cooling fins attached to the equalizer and barrel portion of the cylinder; 8. draft tube surrounding said fins; and means forcausing a flow of cooling air throu h said draft tube toward the head portion 0 the cylinder.

In testimoply whereof I aflix m signature.

0. ARLES F. KET ERING. Witnesses:

J. W. McDonr-xw, HAZEL Sonmmmaonn.

fluid over the cylinder. 7 

